Seismic Critical Angle Model for Shallow Gas Hydrate Quantification
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Solution Overview
Problem
Conventional seismic survey techniques for characterizing shallow subterranean structures lack accuracy in identifying and quantifying materials like gas hydrates, particularly in shallow sediment layers, due to reliance on near offset survey data.
Innovation Solution
A method and system that utilize a critical angle model to correlate material concentrations with respective critical angles, producing a profile based on seismic data to determine the quantity of materials like gas hydrates at specific depths, employing a rock physics model and Bayesian inversion techniques for accurate estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional seismic survey techniques are used for shallow subterranean structures, then survey operations can be performed, but measurement precision deteriorates due to reliance on near offset survey data
Solution Approach 1:
The patent changes the parameter of seismic wave propagation angle from near-offset (conventional) to critical angle (invention). By specifically targeting critical angle refraction events and using a critical angle model that correlates material concentrations with critical angles, the method achieves improved measurement precision for shallow subterranean materials while maintaining reliability through a specialized analytical approach.
2Measurement precision
If conventional seismic survey techniques are used, then survey operations can be performed, but data accuracy deteriorates in shallow sediment layers
Solution Approach 1:
The patent segments the seismic survey methodology by focusing specifically on critical angle refraction events rather than processing all seismic data. By identifying and analyzing only the critical angle portion of the seismic wave propagation, the method simplifies the analytical process while improving data accuracy for shallow materials, avoiding the complexity of processing near-offset data across all angles.
3Measurement precision
If critical angle model is employed to determine material quantities, then measurement precision improves, but device complexity increases due to additional processing steps
Solution Approach 1:
The patent introduces a critical angle model as an intermediary between the seismic survey data and the material quantity determination. This model serves as a bridge that translates critical angle measurements into material concentration information, improving precision while managing complexity by providing a structured framework for the inversion process rather than attempting direct analysis of raw seismic data.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides improved data accuracy and robustness in identifying and quantifying gas hydrates, offering precise concentration measurements at different depths, enhancing the reliability of seismic survey results.
Implementation Method 1
one or more seismic sources are activated to produce seismic waves that are propagated into the subterranean structure. Portions of the seismic waves are reflected from the subterranean structure and received by seismic sensors.
Implementation Method 2
produce a profile based on measured survey data, where the profile contains indications corresponding to refraction events at different depths in a subterranean structure
Data Source
AI summary
A profile is produced based on measured survey data, where the profile contains indications corresponding to refraction events at different depths in a subterranean structure. Based on the profile and a critical angle model that correlates different concentrations of a given material to respective critical angles, a quantity of the given material in a subterranean structure at a particular depth is determined.